1. Technical Field
The present invention relates to an electronic unit which is mounted on a vehicle such as a car and which can be achieved without using any heatsink.
2. Background Art
<Background-Art Measure Against Heat Radiation>
Recently, an electronic unit mounted on a vehicle is requested to be miniaturized due to the limitation of an installation space. In some cases, a plurality of heating components such as semiconductor relays mounted in the electronic unit may thermally interfere with one another and reach very high temperature locally. In order to prevent any electronic component or any electronic substrate from exceeding its upper limit of allowable temperature on this occasion, a heatsink, a metal core substrate, or the like has been used to radiate heat (see JP-A-2011-14574).
<Problem of Background-Art Measure Against Heat Radiation>
As described above, heat radiation performed by use of a heat radiating component such as a heatsink or a metal core substrate is effective as a measure against heat radiation. However, a space for installing the heat radiating component is required. This is against the miniaturization trend. In addition, it is necessary to spend cost for the heat radiating component. The increase of the cost becomes an issue.
The present invention has been accomplished in consideration of the aforementioned circumstances. An object of the invention is to provide a heatsink-less electronic unit in which a measure against thermal interference has been taken into consideration in such a manner that only the layout of heating components is devised without using any heat radiating component such as any heatsink or any metal core substrate to thereby prevent any electronic component or any electronic substrate from exceeding its upper limit of allowable temperature so that deterioration of the electronic component or output stop caused by self-protective shutdown due to overtemperature can be prevented.